Internal surge dampening baffles for flexible tanks and tanks having such baffles

ABSTRACT

An internal baffle apparatus for use within tanks, in particular flexible tanks, for liquids for dampening surges of liquid, and tanks having such baffle apparatus, wherein the baffle apparatus comprising a plurality of panel members connected along a connection line that defines an axis wherein said panel members extend radially from the axis such that each panel member is oriented in a radial plane, and each panel member having a bottom edge, a top edge portion and a remote edge opposite the axis, wherein the bottom edge of each panel includes first connector means operable for connecting the bottom edge at a plurality of connection points to the bottom wall of the tank, and the top edge portion includes second connector means located remote from the axis that are operable to connect the top edge portion to an upper part of the tank.

FIELD OF THE INVENTION

The present invention generally relates to flexible tanks for liquids, and more particularly to flexible storage tanks of the type comprised of a fluid resistant fabric material which when filled may be transported by vehicle or air carrier to a desired location and when emptied may be rolled and/or folded into a compact size for return transport and refilling.

BACKGROUND OF THE INVENTION

Flexible containers are used for the handling, storage and transportation of large volumes of liquids, such as water or fuel, to remote sites where such liquids are needed. These containers are commonly referred to as bladder or pillow tanks, and they are typically rectangular so that they can be efficiently loaded onto vehicles or airplanes for transportation. Examples of some prior art flexible liquid containers are found in U.S. Pat. Nos. 4,573,508 to Knaus and 5,499,743 to Blumenkron. The containers found in Knaus and Blumenkron are relatively lightweight and compactable when not filled with a liquid as they have no frame or rigid supports. These containers are formed of a flexible fiber reinforced elastomeric material and have inlets or nozzles at the sides for filling and draining purposes.

While pillow tanks provide an efficient means of transporting large volumes of liquid, these kinds of flexible tanks have an inherent tendency to allow the free flow of liquid within them, which can lead to liquid surges as a result of the acceleration and deceleration of the liquid. It has long been recognized that free flowing liquids can be dangerous to the balance and control of vehicles. For example, the liquid weight may shift quickly and dramatically to the outside of a tank during a turn, which can upset the balance of the supporting vehicle. At best, this hinders proper vehicle control; at worst, the shifting weight can cause the vehicle to roll over.

Accordingly there is a need for a flexible tank for liquids having an apparatus by which the wave or liquid current forces may be dampened. The devices of the present invention are provided to fulfill this need as will be understood from the following description.

SUMMARY OF THE INVENTION

The above shortcomings may be addressed by providing, in accordance with one aspect of the invention, a flexible tank for liquids having an internal baffle therein for dampening surges of liquid wherein the internal baffle includes a plurality of panel members connected along a connection line that defines an axis, and the panel members extend radially from the axis such that each panel member is oriented in a radial plane. Each panel member has a bottom edge, a top edge portion and a remote edge opposite the axis, and the bottom edge of each panel is connected at a plurality of connection points to the bottom wall of the tank, and the top edge portion further includes connector means located remote from the axis that connects the top edge portion to an upper part of the tank. The connector means may be a ring connected to the top edge portion of the panel, a loop connected to an upper part of the tank, and a link connecting the ring to the loop. The top edge portion may include floatation means operable for maintaining the top edge portion at the level of liquid within the tank. In some embodiments, the flotation means comprises a dense foam block mounted to the top edge portion of the panel member. In some embodiments, the bottom edge of each panel member is connected along its entire length to the bottom wall of the tank.

In another aspect of the invention, there is provided a flexible container for liquids having an internal baffle therein for dampening surges of liquid wherein the internal baffle comprises a flexible rectangular first panel sheet and a flexible rectangular second panel sheet, each having a bottom edge portion and a top edge portion. The bottom edge portion of each panel is connected along its length to the bottom wall of the tank, and the top edge portion of each panel is connected to an upper part of the tank at two locations along the length of the top portion remote from each other. The first flexible panel sheet and second flexible panel sheet are connected to each other along a transverse midline in a manner that the panel sheets are able to define an X shape configuration when viewed from above. The top edge portion may include floatation means operable for maintaining the top edge portion at the level of liquid within the tank. In some embodiments, the panel sheets are made of a thermoplastic-coated fabric such as a heavy duty PVC-coated nylon fabric.

In another aspect of the present invention, there is provided an internal baffle apparatus for use within a tank for liquids for dampening surges of liquid comprising a plurality of panel members connected along a connection line that defines an axis, and the panel members extend radially from the axis such that each panel member is oriented in a radial plane. Each panel member includes a bottom edge, a top edge portion and a remote edge opposite the axis. The bottom edge of each panel includes first connector means operable for connecting the bottom edge at a plurality of connection points to the bottom wall of the tank, and the top edge portion includes second connector means located remote from the axis that are operable to connect the top edge portion to an upper part of the tank. Some embodiments may include floatation means operable for maintaining the top edge portion at the level of liquid within the tank, and the flotation means may comprise a dense foam block mounted to the top edge portion of the panel member. The connector means may comprise a ring connected to the top edge portion of the panel, a loop that is connectable to an upper part of the tank, and a link connecting the ring to the loop. In some embodiments, the baffle has four rectangular flexible panels that are connected along the central connection line.

Other aspects and features of the present invention will become apparent to those of ordinary skill in the art upon review of the following description of specific embodiments of the invention in conjunction with the accompanying figures.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the present invention and to show more clearly how it may be carried into effect, reference will now be made by way of example to the accompanying drawings in which:

FIG. 1 is a top plan view of a pillow tank showing an embodiment of an internal baffle apparatus in phantom lines;

FIG. 2 is a perspective view of the internal baffle apparatus of FIG. 1;

FIG. 3 is a perspective view of an embodiment of a connector apparatus for connecting each of the four corners of the baffle apparatus to an upper inside surface of the tank;

FIG. 4 is a perspective view of a portion of the connector apparatus in FIG. 3;

FIG. 5 is a top plan view a baffle panel sheet;

FIG. 6 is a cross section along line B-B in FIG. 2;

FIG. 7 is a longitudinal section along line A-A in FIG. 2;

FIG. 8 is another embodiment of an internal baffle apparatus in accordance with the present invention;

FIG. 9 is a section along line A-A in FIG. 8; and

FIG. 10 is a perspective of a pillow tank as it may be transported on a vehicle.

DETAILED DESCRIPTION

For the purposes of promoting an understanding of the principles of the invention, reference will now be made to the exemplary embodiments illustrated in the drawings, and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended. Any alterations and further modifications of the inventive features illustrated herein, and any additional applications of the principles of the invention as illustrated herein, which would occur to one skilled in the relevant art and having possession of this disclosure, are to be considered within the scope of the invention. Therefore, specific details disclosed herein are not to be interpreted as limiting, but rather as a basis for the claims and as a representative basis for teaching one skilled in the art to employ the present invention.

Referring to FIG. 1, a flexible liquid storage tank, also known as a pillow tank, 1 is shown in a top plan view with an internal baffle apparatus 10 shown in phantom lines. The baffle apparatus 10 is shown in an operable configuration being that of an X-shape configuration that is oriented longitudinally to the rectangular pillow tank 1. Accordingly, the internal baffle apparatus presents liquid barriers within the tank that interfere with liquid movement within the tank in many directions to dampen liquid surges resulting from acceleration or deceleration of the pillow tank. Pillow tank 1 also includes a filler vent and cap 5 on the top skin or wall 2 and a number of strap holds 6 used for securing the tank for transport. As would be known to persons skilled in the art, other features may also be included on the pillow tank but are not described herein. Pillow tank 1 may be transported by vehicle (such as on a truck as illustrated in FIG. 10), rail or aircraft.

Referring to FIG. 2, there is shown in an embodiment of an internal baffle apparatus 10 in accordance with the present invention shown connected to the inside surface of the bottom skin or wall 3 of a flexible tank. Internal baffle apparatus 10 comprises two identical rectangular flexible baffle panel sheets 12 and 14 that are connected to each other along their transverse midline by a central bond or weld 18 that enables the panel sheets to be arranged in a generally X shaped pattern (as illustrated) which is the operable configuration of this embodiment of the internal baffle apparatus. Accordingly, each half portion of a panel sheet (12 or 14) defines a panel member, and these panel members are operably connected along the central weld or connection line that defines axis 19. Thus the panel members extend radially from the central weld such that each panel member is oriented in its own radial plane that is parallel to the axis 19.

The baffle panel sheets 12 and 14 are primarily constructed from a heavy-duty polymer coated fabric such as, for example, vinyl or urethane coated fabric; specifically, in some embodiments the heavy-duty polymer coated fabric may be a polyurethane coated polyester fabric. The seams during manufacture are either sewn or radio frequency (RF) welded together. However it is contemplated that other suitable material or fabrics may be used in accordance with the present invention and other suitable methods of joining the material or fabrics may be used as would be apparent to persons skilled in the art.

Each of the baffle panel sheets 12 and 14 have a bottom edge 20, remote or side edges 22 that are remote from the central weld 18, top edge portions 24 and top corner portions 23 that are defined by the top edges and side edges. A central aperture 26 is provided along the bottom edge 20 spanning the midline of the baffle panel to allow a reduced flow of liquid between sections during filling and emptying of the tank. A strap 30 made of a webbing material is sewn onto each top corner portion 23 and the free and of the strap 30 is connected to a D-ring 32. Along the top edge portion 24 is include floatation means such as floats 36, each comprising a dense foam block held within a pocket of the panel material as described below. The foam material is one that is buoyant with respect to the liquid for which the pillow tank is intended to be used. The side edges 22 include a reinforcement strip 42 which comprises a strip of the panel material at the edge folded over itself and RF welded into place. The bottom edges of the baffle panels are connected to the bottom skin 3 of the pillow tank by RF welding the bottom edges to connecter strips 40 that are themselves RF welded to the bottom skin 3 of the pillow tank. Accordingly, the bottom edges 20 are fixed on the bottom skin. Alternatively, the bottom edges 20 may be connected to the bottom skin at a plurality of connection points as opposed to along its entire length as in FIG. 2.

Referring to FIGS. 3 and 4, an embodiment of connector means or corner connector is shown generally at 46 and is used to secure each top corner 23 of the baffle panel sheets to an inside surface 48 of the top skin of the tank. Alternatively, the corner connector 46 can be located on the high-inside surfaces of the side or end skins of the pillow tank. Accordingly, the top corner portions 23 of the baffle panels are connected to, hence move in conjunction with, upper portions of the pillow tank as the tank expands or contracts during filling or emptying respectively. Corner connector 46 comprises a base patch 50 of a suitable material, such as a heavy-duty polymer coated fabric as described above (usually the same material as used for the tank walls) onto which is sewn a loop 52 of a strong webbing material. The base patch 50 is RF welded to the inside surface 48 of the top skin (or high-inside surface of a side skin). A reinforcement patch 54 of the same polymer coated fabric material having a central aperture 56 is provided whereby the loop 52 is threaded through the central aperture 56 and the reinforcement patch 54 is RF welded onto the base patch 50. A quick connect link 58 is used to connect D-ring 32 of a top corner portion to loop 52. A soft cover 60, such as a hose cover, encloses the loop 52, the quick connect link 58 and the D-ring 32 to protect the tank skin from abrasion. A corner connector apparatus is provided for each of the four top corners of the baffle apparatus and is affixed to the inside surface of the tank to maintain the baffle apparatus in an operable orientation such as the X-shape illustrated in FIGS. 1, 2 and 8. While an embodiment of the connector means has been described, alternative designs and configurations of connector means are contemplated and would be apparent to persons skilled in the art, and are considered to be within the scope of the present invention.

Referring to FIG. 5, there is illustrated a baffle panel sheet pattern 62 showing the various seams and folds used to construct the finished baffle panel sheets. The top edge portion 24 of each baffle panel sheet is constructed from a longitudinal band portion 64 and two longitudinal half portions 66. Each half portion 66 is folded over the adjacent portion of the longitudinal band 64. A foam block is inserted in between the half portion 66 and the adjacent portion of the longitudinal band 64, and the material of the half portion and band portion around the foam block is RF welded together so as to form a sealed pocket that contains the foam block. While this is one method of securing floatation means to the top edge portion of the panel, there are numerous alternative methods that would be apparent to those skilled in the art. The side edges of the panels have a narrow side flap 68 that is folded over and welded to provide the reinforcement strip 42. Bottom flaps 70 provided longitudinally along the bottom edge are welded to the connector strip 40 on the bottom skin of the tank to secure the bottom edge of the panels to the tank.

Referring to FIG. 6, a cross section of a top edge portion 24 is shown through the foam block 72 and illustrates the pocket formed around the foam block by the material of the longitudinal band 64 being welded 74 to the material of the half portion 66.

Referring to FIG. 7, there are illustrated in longitudinal section showing two baffle panel sheets 12 and 14 connected to each other along their transverse midline by central weld 18, which enables the two panels sheets to be oriented in a generally X-shaped configuration with the panel members extend radially from the central weld. Reinforcing interconnecting material 76 are welded to portions of panel sheets 12 and 14 that are adjacent each other on each side of the central weld to provided additional structural support to the central weld.

Referring to FIGS. 8 and 9, there is shown another embodiment of an internal baffle apparatus 110 of the present invention. As in the previous embodiment, internal baffle apparatus 110 comprises two baffle panel sheets 112 and 114 that are connected to each other along their transverse midline by a central weld 118 that enables the panel sheets to be arranged in a generally X shaped pattern. As well, each of the internal baffle panel sheets 112 and 114 has a bottom edge 120, side edges 122, top corner portions 123 and top edge portions 124. A central aperture 126 is provided along the bottom edge 120 spanning the midline of the baffle panel sheets. A strap 130 made of a webbing material is sewn onto each of the top corner portions 123 and the free and of the strap 130 is connected to a D-ring 132. Along the top edge portion 124 include floatation means such as floats 136, each comprising a foam block held within a pocket of the panel material as described above. However, in contrast to the previously described embodiment, the bottom edges 120 of the baffle panels are provided with a plurality of holes along the length of the bottom edge. Connector strips 140 comprise a vertical strip 141 that also includes a plurality of holes 142 along its length, and horizontal portions 144 and 145 that are welded to the bottom skin of the tank to affix the connector strip 140 thereto. The holes 142 of the connecter strip are aligned with the holes in the bottom edge 120 of the panels and the bottom edge 120 is connected to the vertical strip 141 (hence the bottom of the skin) by threading a suitable twine through the aligned holes, or by other suitable means. This embodiment may be preferred in applications requiring the use of large internal baffle apparatus in large volume flexible tanks since the ability to RF weld the baffle panels to the bottom skin of the tank may be hampered by the size limitations of the production equipment used in the manufacture of the flexible tanks. These alternate means of connecting the bottom edges of the baffle panels has been found to avoid such limitations. The top corner portions 123 are connected to the inside of the tank as described previously.

In the illustrated embodiments of the present invention, the bottom edges of the panels are connected to the bottom skin of the flexible tank and the top corners are connected to the upper inside portions of the tank such that the baffle apparatus is oriented so as to generally define an X shape that is aligned longitudinally with the tank, or that is preferably aligned with the principal direction in which liquid surges are expected. While in the illustrated embodiments, the bottom edges of the panel sheets are shown connected to the bottom skin of the tank along their entire length, it is also possible to have a plurality of discrete connection points along the bottom edge for securing the bottom edge to the bottom skin of the tank. In an empty flexible tank, the baffle apparatus is in a collapsed state and does not occupy any significant space given its flexible construction. As the liquid level in the tank rises during filling, the rising upper portion of the tank (such as the top skin) to which the top corners of the baffle panels are connected, pulls the top portion of the baffle apparatus upwards. This is aided by the buoyancy of the floats along the top edges of the panels which maintain the top edges at or slightly above the liquid level. While a float system is described in the illustrated embodiment, it is also possible to have multiple connection points along the length of the top edge portion of the baffle panel sheets which are connected to the top skin of the tank for maintaining the top edge portion above the fluid level in the tank, instead of the floats. However, the multiple connectors required would add complexity in the manufacture of the tanks and reduce the flexibility of the baffle apparatus.

With the bottom edges secured to the bottom skin of the tank, and the four corners secured to the top portion of the tank, the baffle apparatus has enough lateral resistance to significantly retard the movement of liquid within the tank, thereby dampening dangerous liquid surges that could impair the handling of the vehicle carrying the tank. The baffle apparatus successfully limits liquid surges regardless of the liquid level in the tank. As an example, a 3000 USG tank, filled with 1235 Imperial gallons of water and having a baffle apparatus of the present invention installed, was able to dampen the liquid surges caused by rapid deceleration in 8 seconds. Whereas in a regular tank filled with 1235 Imperial gallons but without such baffle apparatus, the liquid surges continued for approximately 4 minutes and 30 seconds.

The embodiments of the invention illustrated comprise two panel sheets secured together to define an X-shaped baffle apparatus in the operable configuration, and this configuration has been found to be very effective in dampening fluid surges in tanks of varying sizes. It is conceivable to use only one panel sheet oriented across the primary fluid surge with reasonable dampening results in some applications, or more than two panel sheets in other applications, or a plurality of individual panel members connected to each other to define a baffle apparatus having a more complex configuration. However, there will be a point of diminishing returns where the increased complexity and cost of a more complex baffle apparatus will outweigh the slight increase in fluid dampening effectiveness that such apparatus yield over that of simpler configurations.

While the above description and illustrations constitute preferred or alternate embodiments of the present invention, it will be appreciated that numerous variations may be made without departing from the scope of the invention. 

1. A flexible tank for liquids having an internal baffle therein for dampening surges of liquid wherein the internal baffle comprises a first flexible panel sheet having a bottom edge portion and a top edge portion, the bottom edge portion is connected to the bottom wall of the tank at a plurality of connection points, and the top edge portion is connected to an upper part of the tank at two or more locations along the top edge portion that are remote from each other.
 2. The apparatus of claim 1 wherein the top edge portion further includes floatation means operable for maintaining the top edge portion at the level of liquid within the tank.
 3. The apparatus of claim 2 wherein the panel defines one or more apertures for allowing limited flow of liquid through the panel.
 4. A flexible tank for liquids having an internal baffle therein for dampening surges of liquid wherein the internal baffle comprises: a plurality of panel members connected along a connection line that defines an axis wherein said panel members are able to extend radially from the connection line such that each panel member is oriented in a radial plane; and each panel member has a bottom edge, a top edge portion and a remote edge opposite the axis, wherein the bottom edge of each panel member is connected at a plurality of connection points to the bottom wall of the tank, and the top edge portion further includes connector means located remote from the axis that connects the top edge portion to an upper part of the tank.
 5. The apparatus of claim 4 wherein the radial plane of each panel member is parallel to the axis.
 6. The apparatus of claim 4 wherein the top edge portion further includes floatation means operable for maintaining the top edge portion at the level of liquid within the tank.
 7. The apparatus of claim 6 wherein the bottom edge of each panel member is connected along its entire length to the bottom wall of the tank.
 8. The apparatus of claim 7 wherein the flotation means comprises a dense foam block mounted to the top edge portion of the panel member.
 9. The apparatus of claim 8 wherein the connector means comprises a ring connected to the top edge portion of the panel, a loop connected to an upper part of the tank, and a link connecting the ring to the loop.
 10. The apparatus of claim 9 wherein each panel defines one or more apertures for allowing limited flow of liquid through the panel.
 11. The apparatus of claim 10 wherein the plurality of flexible panel members comprises four rectangular flexible panels that are connected along a central connection line defining said axis.
 12. A flexible container for liquids having an internal baffle therein for dampening surges of liquid wherein the internal baffle comprises a flexible rectangular first panel sheet and a flexible rectangular second panel sheet, each flexible panel includes a bottom edge portion and a top edge portion, wherein the bottom edge portion of each panel is connected along its length to the bottom wall of the tank, and the top edge portion of each panel is connected to an upper part of the tank at two locations along the length of the top portion remote from each other, and the first flexible panel sheet and second flexible panel sheet are connected to each other along a transverse midline in a manner that said panels sheets are able to define an X shape configuration when viewed from above.
 13. The apparatus of claim 12 wherein the top edge portion includes floatation means operable for maintaining the top edge portion at the level of liquid within the tank.
 14. The apparatus of claim 13 wherein the panel sheets are made of a polymer coated fabric.
 15. The apparatus of claim 13 wherein the panel sheets are made of a polyurethane coated polyester fabric.
 16. An internal baffle apparatus for use within a tank for liquids for dampening surges of liquid, the baffle apparatus comprising: a plurality of panel members connected along a connection line that defines an axis wherein said panel members extend radially from the axis such that each panel member is oriented in a radial plane; and each panel member having a bottom edge, a top edge portion and a remote edge opposite the axis, wherein the bottom edge of each panel includes first connector means operable for connecting the bottom edge at a plurality of connection points to the bottom wall of the tank, and the top edge portion includes second connector means located remote from the axis that are operable to connect the top edge portion to an upper part of the tank.
 17. The apparatus of claim 16 wherein the top edge portion further includes floatation means operable for maintaining the top edge portion at the level of liquid within the tank.
 18. The apparatus of claim 17 wherein the flotation means comprises a dense foam block mounted to the top edge portion of the panel member.
 19. The apparatus of claim 18 wherein the connector means comprises a ring connected to the top edge portion of the panel, a loop that is connectable to an upper part of the tank, and a link connecting the ring to the loop.
 20. The apparatus of claim 19 wherein each panel defines one or more apertures for allowing limited flow of liquid through the panel.
 21. The apparatus of claim 20 wherein the plurality of flexible panel members comprises four rectangular flexible panels that are connected along a central connection line defining said axis. 